Hepatocellular carcinoma (HCC) is the most common liver cancer with high mortality rate in patients suffering from liver diseases. The drug of choice used in advanced-stage of HCC is sorafenib. However, adaptive resistance has been observed in HCC patients undergoing long-term sorafenib treatment, lowering its effectiveness. Hence, it is important to overcome drug resistance to improve overall management of HCC. Here, we have identified a candidate biomarker for sorafenib resistance in a HCC model cell line, HepG2. Initially, comparative proteomic profiling of parental HepG2 [HepG2 (P)] and sorafenib-resistant HepG2 [HepG2 (R)] cells was performed via MALDI (matrix-assisted laser desorption/ionization) which revealed the deregulation of vimentin in HepG2 (R) cells. Gene and protein level expression of vimentin was also observed through quantitative real-time polymerase chain reaction (qRT PCR) and fluorescence-activated cell sorting (FACS), respectively. Furthermore, withaferin A was used to study regulation of vimentin expression and its significance in sorafenib resistance. Both gene and protein level of vimentin expression was found to be downregulated in HepG2 (R) in comparison to HepG2 (P). Interestingly, the study demonstrated that withaferin A further lowered the expression of vimentin in HepG2 (R) cells in a dose-dependent manner. Also, inhibition of vimentin lowered ABCG2 expression and decreased cell viability in parental as well as sorafenib resistant HepG2 cells. Hence, our study for the first time highlighted the probable therapeutic potential of vimentin in sorafenib resistant HepG2, a HCC model cell line.

In most cancers, tumor hypoxia downregulates the expression of C‐C motif chemokine 2 (CCL2), and this downregulation has been implicated in monocyte infiltration and tumor progression; however, the molecular mechanism is not yet clear. We compared noncancerous and lung‐adenocarcinoma human samples for hypoxia‐inducible factor 1‐alpha (HIF‐1A), microRNA‐210‐3p (mir‐210‐3p), and CCL2 levels. Mechanistic studies were performed on lung adenocarcinoma cell lines and 3D tumor spheroids to understand the role of hypoxia‐induced miR‐210‐3p in the regulation of CCL2 expression and macrophage polarization. HIF‐1Α stabilization increases miR‐210‐3p levels in lung adenocarcinoma and impairs monocyte infiltration by inhibiting CCL2 expression. Mechanistically, miR‐210‐3p directly binds to the 3′untranslated region (UTR) of CCL2 mRNA and silences it. Suppressing miR‐210‐3p substantially downregulates the effect of hypoxia on CCL2 expression. Monocyte migration is significantly hampered in miR‐210‐3p mimic‐transfected HIF‐1A silenced cancer cells. In contrast, inhibition of miR‐210‐3p in HIF‐1A‐overexpressed cells markedly restored monocyte migration, highlighting a direct link between the miR‐210‐3p level and tumor monocyte burden. Moreover, miR‐210‐3p inhibition in 3D tumor spheroids promotes monocyte recruitment and skewing towards an antitumor M1 phenotype. Anti‐hsa‐miR‐210‐3p‐locked nucleic acid (LNA) delivery in a lung tumor xenograft zebrafish model caused tumor regression, suggesting that miR‐210‐3p could be a promising target for immunomodulatory therapeutic strategies against lung adenocarcinoma.

MicroRNA-122 (miR-122) is liver specific and plays an important role in physiology as well as diseases including hepatocellular carcinoma (HCC). Downregulation of miR-122 in HCC modulates apoptosis. Similarly, the putative targets of miR-122, the forkhead box (FOX) family genes also play an important role in the regulation of apoptosis. Hence, an interplay between miR-122 and FOX family genes has been explored in this study. Initially, an augmentation of apoptosis was noticed in HepG2 cells after transfection with miR-122. Further, the predicted miR-122 targets, the FOX family genes ( FOXM1b, FOXP1, and FOXO4) were selected via in silico analysis based on their role in apoptosis. We checked the expression of all these genes at transcript level after the transfection of miR-122 and found that the relative expression of FOXP1 and FOXM1b was significantly downregulated (p < 0.005) and that of FOXO4 was upregulated (p < 0.005). Thus, the finding indicates deregulation of these FOX genes as a result of miR-122 augmentation might be involved in the modulation of apoptosis. Impact Statement: Here, we have investigated the crosstalk between microRNA-122 (miR-122) and selective FOX family genes in HepG2 cells. miR-122 is a prominent miRNA in liver and has been reported to be downregulated in hepatocellular carcinoma (HCC). It has been speculated that diminished level of miR-122 during HCC might be one of the reasons for tumor progression. However, the exact molecular interactions are not clear yet. This study unravels one of the molecular mechanisms of miR-122 through which it might impact the tumorigenesis of HCC.